I think the only difference is the price. dynamat is expecive in the long run. I don't think there is a difference in the product. there is also a product called eDead. I just heard that it doesn't have a smell. Your best bet for large gaps is to use both a "soft" spray foam or an upholstery foam and the Dynamat (or whatever you choose). don't forget that if you have that black plastic peice under your bumper to do something with that...cause that rattles like an sob
Last edited by NoMe4u; 01-07-2008 at 11:28 AM.